1. Field of the Invention
This invention relates to a distance measuring device for a camera of the type arranged to project a light from a light projecting element on an object to be photographed and to measure a distance to the object by detecting with a light sensitive element the light as it is reflected by and coming from the object.
2. Description of the Prior Art
Generally, the conventional distance measuring systems of the type arranged to measure a distance to an object to be photographed by projecting a light from a light projecting element onto the object have been incapable of discerning the light projected on and reflected by the object from the light of the object when the object happens to be of a high degree of brightness. Accordingly, in such a case, the camera either has become incapable of performing a photographing operation or has performed out-of-focus photographing. The conventional solutions of this problem have included a method of using a light projecting LED (light emitting diode) of high output and another method of shortening the measurable range of distance to ensure that the light projected from the light projecting element can be received in sufficient intensity after it is reflected by the object. However, use of an LED of high output not only result in a higher cost but also result in increased power consumption. Particularly, in the case of cameras which are generally required to be in a compact size, the capacity of a battery usable for them is limited. The first solution, therefore, have caused a great inconvenience. Meanwhile, the other solution of shortening the measurable range of distance is hardly compatible with the purposes and usages of cameras.